For many years, the poultry industry has been interested in feed additives and other methods of increasing the feed efficiency of chickens, turkeys and other forms of poultry. Because of the large amounts of feed consumed by poultry and the small margin of return on capital invested in raising chickens, turkeys, etc., even increases as small as 1% are meaningful economically. The term feed efficiency generally is based upon measuring the amount of weight gain in relation to the amount of feed consumed. Considerations such as feed efficiency also apply to other animals raised as food.
A variety of additives have been suggested for use in raising animal feed efficiency. Of some relevance to the present invention is U.S. Pat. No. 3,823,072 to Hooreman which teaches that a bacteria, Streptomyces fradiae produces substances having enzymatic activity. Specifically, the fermentation products of S. fradiae are useful in reducing the viscosity of intestinal mucous to a level between trypsin and chymotrypsin. Animals receiving feed containing the enzymatic extract are said to experience an increase in feed efficiency. Apparently the enzyme extract permits nutrients of digested food to more easily pass through the mucous membrane which covers the wall of the intestine. It is stated that excessive reduction in mucous viscosity should be avoided because in this situation a counterreaction is engendered, i.e. mucous production is actually stimulated. Hooreman further states that useful enzymes must not be inhibited by trypsin inhibitors.